JP2018515059A - Method of operating a fluid delivery system - Google Patents

Abstract

The present invention relates to a method for operating a fluid delivery system comprising a fluid discharge pump, a voltage manipulator (7) and an electric motor (8), wherein the fluid delivery system is integrated in a power network. The electric motor (8) can be driven and controlled by the voltage applied to the electric motor (8), and the voltage manipulator (7) is connected in front to the electric motor (8). A step of determining a desired fluid discharge rate, a step of determining a required rotation speed of the fluid discharge pump for conveying the desired fluid discharge volume, and a requirement for achieving the required rotation speed of the fluid discharge pump And a step of operating a voltage manipulator to achieve the required voltage.

Description

  The present invention relates to a method of operating a fluid delivery system comprising a fluid discharge pump, a voltage manipulator, and an electric motor. The fluid conveyance system here is integrated in a power supply network, the electric motor can be driven and controlled by a voltage applied to the electric motor, and the voltage manipulator is connected in front of the electric motor.

BACKGROUND ART In a fuel transfer system, a fuel discharge pump is used to transfer fuel from a fuel tank to an internal combustion engine. For this conveyance, an electrically driven fuel discharge pump is used, and this fuel discharge pump has a pump module that can be driven by an electric motor. Fuel delivery pumps must ensure fuel delivery over a wide operating range. For example, the fuel discharge pump must provide a sufficient discharge amount even when the internal combustion engine is fully loaded, even when the traveling speed of the automobile is low or in a stopped state.

  The maximum possible discharge capacity, on the other hand, depends on the structure of the fuel discharge pump. In this case, the maximum discharge amount increases as the size of the fuel discharge pump increases. The maximum possible discharge capacity, on the other hand, depends on the rotational speed of the pump module, which is determined decisively by the power level. Therefore, the maximum discharge amount directly depends on the supply voltage of the electric motor and the current intensity applied to the electric motor.

  The voltage used in the vehicle's onboard power supply network is uniformly limited to a predetermined maximum value, so the voltage at the fuel discharge pump cannot be increased arbitrarily, and therefore the maximum speed and the maximum associated with it. The discharge amount is limited.

  In the prior art, devices with additional boosters are known for increasing the voltage to the fuel discharge pump. The booster here is formed by an electric circuit composed of a plurality of components, for example.

  A drawback in the devices known from the prior art is that the use of a booster causes an undesirable power loss in the power grid during operation. This power loss is caused in particular by the additional inductance of the booster and the power semiconductor used for the booster. Furthermore, the booster is not optimally driven and controlled in order to optimally compensate for the generated defects.

PROBLEM, SOLUTION AND ADVANTAGE OF THE INVENTION Therefore, the object of the present invention is to enable optimum operation of the booster, increase the maximum discharge rate of the fuel discharge pump and at the same time minimize the power loss caused by the booster Is to provide.

  The problem with this method is solved by a method having the features of claim 1.

Embodiments of the present invention relate to a method of operating a fluid delivery system comprising a fluid discharge pump, a voltage manipulator, and an electric motor, where the fluid delivery system is integrated into a power supply network and the electric motor Can be driven and controlled by the voltage applied to the electric motor, and the voltage manipulator is connected in front of the electric motor. Here, the following steps are executed. That is,
Determining a desired fluid discharge rate;
Obtaining a required number of rotations of a fluid discharge pump for conveying a desired fluid discharge amount;
Determining a required voltage to achieve a required rotational speed of the fluid discharge pump;
Activating the voltage manipulator to achieve the required voltage is performed.

  In particular, the fluid transfer system may be a fuel transfer system that transfers fuel from a fuel tank to an internal combustion engine. Furthermore, it can be applied to hydraulic circuits or hydraulic circuits, among others.

  A voltage manipulator is an electronic component that can act on a voltage. The voltage manipulator may be composed of a single component or may be composed of a plurality of combined components. The drive control of the voltage manipulator can be performed, for example, via a control device. As the voltage manipulator, a so-called booster used for amplification and / or attenuation of an electric signal can be used. Here, only the voltage level itself can be changed or, for example, the switching frequency of the signal can be changed. The voltage manipulator is operable to act on the voltage actively, thereby causing, for example, an increase or decrease in voltage. Alternatively, additional functions may be achieved by actuation of the voltage manipulator in addition or instead of increasing and / or decreasing the voltage. For example, the voltage manipulator can act as a filter for the switching frequency of the power grid.

  Using the power network, switching from one or more components is intended, for example, switching from control equipment, energy sources and actuators. This can be constituted, for example, by an onboard power supply network of an automobile. The electric motor of the fluid transfer system is connected to a power supply network so that the number of rotations can be controlled. The number of rotations of the electric motor and the number of rotations of the fluid discharge pump connected to the electric motor are also important criteria for determining the fluid discharge amount of the fluid discharge pump. In order to carry a predetermined desired discharge volume, a certain determinable rotational speed level of the fluid discharge pump is required. This desired rotational speed level can be achieved through applying an appropriate voltage to the electric motor.

  The voltage manipulator can preferably be used to generate an appropriate voltage level in an electric motor. Thereby, a sufficient fluid discharge amount can be guaranteed.

  The fuel transfer system can be driven and controlled by the applied voltage and by setting the rotational speed. However, in this case, there is a relationship depending on each fuel transfer system and operating conditions between the applied voltage and the rotation speed generated in the fuel discharge pump. Also preferably, in a fuel conveyance system that is driven and controlled via the rotational speed, a voltage that must be applied to the fuel discharge pump is required in order to achieve the predetermined rotational speed.

  Particularly preferably, the voltage manipulator is activated when the voltage required to achieve the predetermined rotational speed of the fluid discharge pump is outside a predetermined voltage range.

  The power network is usually operated at a predetermined voltage level. Therefore, the voltage that can be applied to the electric motor from the power supply network is limited. This also limits the maximum possible number of revolutions. This is because the maximum possible number of revolutions depends directly on the voltage to the electric motor. If a rotational speed that requires a voltage above the maximum voltage in the power supply network is required to guarantee the fluid discharge rate, this rotational speed cannot be achieved without changing the voltage. The voltage manipulator can change the voltage of the power supply network appropriately in order to eventually generate a voltage in the electric motor that exceeds the maximum voltage of the power supply network. Therefore, the voltage manipulator can function as a voltage amplifier.

  In the opposite case, a voltage manipulator can also be used to reduce the voltage to a level that cannot be provided from the power grid. This is particularly advantageous because the voltage of the remaining power supply network does not need to be further pulled down unnecessarily, for example because other loads require higher voltage levels. This allows a very low voltage to be applied to the electric motor that results in a very low rotational speed, whereas the voltage of the remaining power supply network remains substantially unchanged.

  In applications without a voltage manipulator, the reduction of the rotational speed can alternatively be achieved, for example, by reducing the modulation frequency of the pulse width modulation signal used for driving control of the electric motor. However, this is not preferred because a reduction in the modulation frequency below a predetermined limit value can cause an adverse acoustic effect.

  The predetermined voltage range is preferably determined by the voltage level of the power supply network.

  One preferred embodiment is characterized by the following. In other words, the power supply network is operated by a predetermined power supply network voltage. In this case, the voltage for driving and controlling the electric motor can be lowered to a level lower than the power supply network voltage by the voltage manipulator. This is advantageous for overall expansion of the available rotational speed range of the electric motor and thus of the fluid discharge pump. The voltage manipulator here functions as a signal attenuator. This is particularly advantageous when the power supply network is operated at very high voltages that are limited only temporarily or are permanently applied to the power supply network. This applies, for example, to electric vehicles that regularly have a significantly higher supply voltage. Very high voltage levels can occur in the power supply network, particularly during the regenerative mode, i.e. during the recovery of electrical energy from the running operation of the electric vehicle.

  Preferably, the power supply network is operated by a predetermined power supply network voltage. In this case, the voltage for driving and controlling the electric motor can be raised to a level exceeding the power supply network voltage by a voltage manipulator. Here, the voltage manipulator functions as a signal amplifier that raises the voltage level of the signal above the voltage level of the power supply network in particular, and this can generate a higher rotational speed even in the electric motor and thus also in the fluid discharge pump. become able to. As a result, the operating bandwidth of the fluid discharge pump can be expanded upward. This is because this voltage amplification enables operation at a higher rotational speed. This increases the rotational speed range of the electric motor and thus the fluid discharge pump. By means already described above, the voltage can be reduced below the voltage level of the remaining power supply network, so that the rotational speed range can be expanded both upwards and downwards as a whole.

  Even more preferably, the voltage manipulator acts as a filter between the electric motor and the rest of the power network.

  Filters are particularly preferred for keeping the difference separated from each other before and after the voltage manipulator, especially at the switching frequency of the signal used. For example, preferably, the switching frequency of the remaining power supply network is significantly higher than the switching frequency between the voltage manipulator and the electric motor. This remaining power grid can be operated at a switching frequency of, for example, about 500 kHz, so that attenuation or filtering of the power grid is performed with simpler components and less cost than with a significantly lower switching frequency. Can do. However, the voltage manipulator may nevertheless be designed such that the electric motor is driven and controlled at a significantly lower switching frequency, which can be present, for example, at 20 kHz to 25 kHz. With this voltage manipulator, a simple separation of the two switching frequency regions can be achieved.

  More preferably, the fluid delivery system is decoupled from the rest of the power network by the voltage manipulator with respect to the switching frequency of the drive control signal, here between the voltage manipulator and the electric motor than between the power network and the voltage manipulator. Low switching frequency is dominant. This is advantageous to allow simple filtering and / or attenuation of the power grid. On the other hand, a drive control signal having an optimum switching frequency as much as possible can be applied to the electric motor.

  Also, for purpose, the voltage output to the electric motor by the voltage manipulator corresponds to the voltage of the remaining power network, where the switching frequency between the electric motor and the voltage manipulator is the switching of the remaining power network. It is different from frequency. This is advantageous because switching frequency decoupling is achieved even if the voltage level remains unchanged.

  Even more preferably, the voltage manipulator is used as an attenuator between the switching frequency of the drive control signal of the electric motor and the switching frequency of the remaining power supply network. The damping function of the voltage manipulator is advantageous in order to achieve the widest possible disconnection from the branch connected downstream to the voltage manipulator and the remaining power supply network.

  More conveniently, the voltage manipulator is formed by a booster, in which case this booster is constructed according to the ZETA principle or the SEPIC principle or the BUCK principle or the BOOST principle. These said principles are known in the prior art and represent an appropriate construction pattern for voltage manipulators.

  Preferably, the voltage generated by the voltage manipulator and introduced into the electric motor is set to a voltage necessary for achieving a predetermined rotational speed of the fluid discharge pump or a voltage necessary for conveying a desired fluid discharge amount. Strictly equivalent. This is advantageous because it allows as much energy efficient operation of the fluid delivery system as possible.

  The use of a voltage manipulator makes it possible to use fluid discharge pumps that are more compactly designed and specifically optimized in terms of energy. In the normal case, the fluid delivery pump can operate in an energetically optimal range and can be pulled up to higher rotational speed levels by use of a voltage manipulator as needed. The efficiency loss inevitably caused by the use of the voltage manipulator can be compensated by operating the remaining power grid, in particular the power module pre-connected to the electric motor, in a particularly optimal range. Energy efficient operation is possible.

  Furthermore, more conveniently, a power module for block rectification is arranged between the voltage manipulator and the electric motor, where the power module operates with a duty ratio of 90% to 100%, The rotation speed of the motor is controlled by the voltage output from the voltage manipulator. A particularly preferred duty ratio in the power module is about 100%.

  Block commutation of the electric motor is achieved via the power module, which makes it possible to operate the brushless DC motor in particular advantageously. The power module can operate at different duty degrees or duty ratios, where the duty ratio indicates the ratio between the pulse duration and the pulse period duration starting from the power module. In order to achieve energetically optimal operation, it is advantageous if the duty ratio is as high as possible, ideally 100%. By operating at a duty ratio of 100%, particularly generated power loss can be optimized by its reduction.

  In applications without a pre-connected voltage manipulator, the speed control of the electric motor can be performed by changing the duty ratio in the power module. However, in that case, an energetically disadvantageous operating situation may occur based on the low duty ratio. This is because power modules in this range generate high power losses. In order to keep the power loss due to the power module as small as possible, it is advantageous to achieve operation of the power module with as high a duty ratio as possible. Due to the pre-connection of the voltage manipulator, the rotation speed of the electric motor can be changed even when the high duty ratio of the power module is maintained as it is.

  By disconnecting the remaining power supply network from the section between the voltage manipulator and the electric motor already described above, it is also possible to operate the power module, in particular at a switching frequency different from the switching frequency of the remaining power supply network. . This is particularly advantageous because both the power module and the rest of the power network can be operated at optimum switching frequencies.

  Preferred developments of the invention are described in the dependent claims and in the following description of the drawings.

  In the following, the present invention will be described in detail based on embodiments with reference to the drawings.

Block diagram for explaining the method steps of the method Block diagram for explaining frequency domain separation by the voltage manipulator in the remaining power supply network and the section between the voltage manipulator and the electric motor

Preferred Embodiments of the Invention FIG. 1 shows a block diagram 1 for explaining the individual method steps of the method according to the invention.

  In block 2, a desired fluid discharge rate is determined. This can be done, for example, via a suitable sensor system or by setting from a control device. In the case of the fluid conveyance system, the fluid discharge amount is periodically strictly grasped in the motor control device and can be provided as a value.

  In block 3, the number of rotations at which the fluid discharge pump must be rotated for the transfer of the corresponding fluid amount is determined from the determined fluid discharge amount. For this purpose, additional values are additionally taken into account, such as the pressure in the fluid delivery system, the temperature of the fluid to be delivered or the viscosity of the fluid to be delivered. The characteristics of the fluid delivery system defined by the respective structural embodiment can be included in the calculation of the rotational speed.

  Block 4 is used to determine the voltage required to allow the electric motor that drives the fluid discharge pump to rotate at the determined rotational speed. The rotational speed of the electric motor can be determined, inter alia, by changing the voltage applied to the electric motor.

  Finally, at block 5, the voltage manipulator is activated to affect the signal amplitude of the voltage signal to achieve a voltage increase or decrease. As a result, the rotation speed of the electric motor is increased or decreased. Particularly preferably, the voltage manipulator can also change the voltage to a value above or below the voltage introduced to it. Further, only the change of the voltage switching frequency can be achieved without increasing or decreasing the amplitude at that time by the operation of the voltage manipulator.

  FIG. 2 shows a block diagram 6 illustrating the interconnection between the voltage manipulator 7 and the electric motor 8. The remaining power supply network is shown on the left side of the voltage manipulator 7. This remaining power network may include, for example, voltage sources, control equipment, and other loads.

  On the right side of the voltage manipulator 7, an electrical section 9 in which the voltage manipulator 7 is conductively connected to the power module 10 is shown. The power module 10 is used for block rectification of the voltage or voltage signal output by the voltage manipulator 7. For example, a brushless DC motor can be driven and controlled by this block rectification.

  A filter 11 is disposed between the voltage manipulator 7 and the power module 10, and the filter 11 is used for filtering the voltage output by the voltage manipulator 7.

  The voltage manipulator 7 is preferably a so-called booster composed of a circuit composed of a plurality of electrical and / or electronic elements. This booster may be constructed according to various principles known in the prior art.

  Particularly preferably, the voltage manipulator 7 can cause a frequency separation between the remaining power supply network shown on the left and the section 9 between the voltage manipulator 7 and the electric motor 8. The section 9 to the electric motor 8 preferably operates at a switching frequency of about 20 kHz, whereas the remaining power supply network operates at a significantly higher switching frequency, for example 500 kHz.

  A further filter is indicated by the reference numeral 12, which allows the filtering of voltage and voltage signals coming from the remaining power supply network before the voltage manipulator 7.

  The embodiment of FIGS. 1 and 2 in particular has no features to be limited and is merely used to clarify the discussion of the present invention. In particular, the voltage manipulator represented by block 7 may be configured in a very wide variety of ways. Also, the connection of the electric motor 8 as shown in FIG. 2 is merely illustrative and does not exclude alternative embodiments.

Claims (12)

A method of operating a fluid delivery system comprising a fluid discharge pump, a voltage manipulator (7), and an electric motor (8),
The fluid transfer system is integrated in a power supply network, the electric motor (8) can be driven and controlled by a voltage applied to the electric motor (8), and the voltage manipulator (7) In the method, connected in advance to the motor (8),
Determining a desired fluid discharge rate;
Obtaining a required number of rotations of the fluid discharge pump for conveying the desired fluid discharge amount;
Determining a required voltage to achieve the required rotational speed of the fluid discharge pump;
Actuating the voltage manipulator (7) to achieve the required voltage.   The method according to claim 1, wherein the voltage manipulator (7) is activated when the voltage required to achieve a predetermined rotational speed of the fluid discharge pump is outside a predetermined voltage range.   The method of claim 2, wherein the predetermined voltage range is determined by a voltage level of the power supply network.   The power network is operated by a predetermined power network voltage, and a voltage for driving and controlling the electric motor (8) can be lowered to a level below the power network voltage by the voltage manipulator (7). 4. The method according to any one of items 1 to 3.   The power network is operated by a predetermined power network voltage, and a voltage for driving and controlling the electric motor (8) can be raised to a level exceeding the power network voltage by the voltage manipulator (7). 5. The method according to any one of items 4 to 4.   The method according to any one of the preceding claims, wherein the voltage manipulator (7) acts as a filter between the electric motor (8) and the rest of the power network.   The fluid transfer system is disconnected from the remaining power network with respect to the switching frequency of the drive control signal by the voltage manipulator (7), wherein between the voltage manipulator (7) and the electric motor (8), The method according to any one of the preceding claims, wherein a switching frequency lower than between the power supply network and the voltage manipulator (7) prevails.   The voltage output to the electric motor (8) by the voltage manipulator (7) corresponds to the voltage of the remaining power supply network, where the voltage between the electric motor (8) and the voltage manipulator (7). The method according to claim 1, wherein a switching frequency is different from a switching frequency of the remaining power supply network.   The voltage manipulator (7) is used as an attenuator between the switching frequency of the drive control signal of the electric motor (8) and the switching frequency of the remaining power supply network. The method according to claim 1.   10. A method according to any one of the preceding claims, wherein the voltage manipulator (7) is formed by a booster, the booster being constructed according to the ZETA principle or the SEPIC principle or the BUCK principle or the BOOST principle.   The voltage generated by the voltage manipulator (7) and introduced into the electric motor (8) is a voltage necessary for achieving a predetermined number of revolutions of the fluid discharge pump or for conveying a desired fluid discharge amount. The method according to claim 1, which corresponds exactly to the voltage required for.   A power module (10) for block rectification is disposed between the voltage manipulator (7) and the electric motor (8), and the power module (10) has a duty ratio of 90% to 100%. 12. A method as claimed in any one of the preceding claims, wherein the method operates and the number of revolutions of the electric motor (8) is controlled by the voltage output by the voltage manipulator (7).

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